The input device which is operated such that the finger or the like contacts or comes close to the screen is formed by employing, for example, a touch panel and used for a smart phone, a car navigation system, or the like. In this kind of input device, instructions intended by a user are inputted into the input device by a specific movement of the finger (hereinafter, referred to as touch operation) performed in such a way as to contact or come close to the touch panel or the like.
In such touch operation, there may be included a gesture operation attended with movement of a position of the finger on the screen of the input device and a tap operation not attended with the movement of the position of the finger. In the gesture operation, a swipe operation performed by sliding a fingertip, a flick operation performed by moving the fingertip quickly, and the like may be included, for example. In the tap operation, a short tap operation in which the screen is pushed short by the fingertip (for example, tapped by the finger), a long tap operation in which the screen is pushed long by the fingertip, and the like may be included, for example.
In the gesture operation attended with the movement of the position of the finger, for example, when a distance of the movement of the finger which contacts the screen of the input device has become not less than a predetermined threshold value, the gesture operation in accordance with the distance and direction of the movement is identified, so that the input operation in response to the identified operation is executed. Further, in the tap operation not attended with the movement of the position of the finger, for example, the operation is identified based on the number of times of contact and the time of contact in the position concerned, and the input operation in response to the identified operation is executed.
However, even in the case of performing the operation such as the tap operation not attended with the movement of the position of the finger, the position of the finger moves slightly depending upon the usage environment or the like, so that the operation not intended by the user may be executed. For example, in the case where the fingertip has moved in the unintended direction due to the shaking or a sudden stop of the vehicle during performing the long tap operation on the touch panel within the vehicle such as an electric car, a motor car or the like, there is the possibility of being erroneously recognized as other gesture operation such as the flick operation, the swipe operation or the like as a result. In addition, when a frequency of such erroneous recognition is increased, the user feels troublesomeness, and the convenience as the input device may be deteriorated.
Hitherto, as a technique for preventing the error recognition with respect to the user operation in the input device using the touch panel or the like, there is known such a device that the threshold value of the movement distance (movement threshold value) for determining the present or absence of the movement of the finger is changed in accordance with pressing force which is applied from the finger to the screen, in order to correctly recognise the movement of the used finger even when a contact area on the screen is changed depending upon the difference of the fingers used for the touch operation. (Japanese Patent Application Laid-Open Publication No. 2014-48971). In this device, by focusing attention on that the contact area and the pressing force on the screen are different when the fingers are different (for example, in the case of the forefinger and the middle finger), the movement threshold value in accordance with the contact area estimated from the pressing force detected on the screen is set up.
However, in the above prior art, although the error recognition caused due to the difference of the fingers or the like may be solved, the error recognition caused due to the vibration, the shaking or the like within the vehicle as referred to above may not be solved.